How i see it, when a group of powerful people wanted to control ETH to some direction or block a party, they needed to do some physical work , which acted as a time-delay lock. Now all they need to do is think about it. I m not sure why the second case has the same level of trust as the first.
I think this begins the search for another trustless transaction system that is neither PoW nor PoS.
With pow, the cash you burn on that mining farm is gone after you give up on your vote or your attack. With PoS, the simple act of being rich means you get more vote, you don't need to burn it or spend it. You even get richer while you do it
If the existing miners don't want to rent to you, you can build your own mining hardware. But if a cartel owns all the ETH and don't want to sell to you, you're SOL.
A cartel that owns all the ETH and doesn't want to let anyone have any? That sort of behavior would quickly reduce the value of the cartel's ETH to zero, on account of it destroying the network. This seems about as likely as you building your own specialized ASIC hardware that could produce within even a order of magnitude of the hashing power per dollar spent that the main mining cartels enjoy.
This argument is straining so hard to find a way in which these two things are different but PoS and PoW are absolutely the same thing, just one of them is cheaper, more decentralized, and cleaner. PoW doesn't imply greater decentralization, in fact it implies the opposite. I can go build a $100 computer right now, load it up with 32 ETH, and begin validating transactions in minutes. I am on an even footing with every other participant investing a similar level of resources. If I want to mine some PoW BTC, for example, i first need the industry alliances to get the latest greatest mining ASICs (which are mostly not available, because the manufacturers are strongly incentivized to use them for themselves and a small group of allies) or I had to get a team of engineers to design one and contract a custom silicon foundry to produce one, wait a year or two, and then plug in my new miners with an enormous capital investment.
It sure seems like one of these is more decentralized, and I don't think it's the one you want it to be.
I think this begins the search for another trustless transaction system that is neither PoW nor PoS.